Adds resource_provider::ResourceProvider

components/resource_provider/resource_provider_impl.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/resource_provider/resource_provider_impl.h"
+
+#include "base/bind.h"
+#include "base/files/file_util.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/sequenced_task_runner.h"
+#include "base/threading/sequenced_worker_pool.h"
+#include "components/resource_provider/file_utils.h"
+
+namespace resource_provider {
+
+// Loading is done on a background thread. The data is passed between the
+// two threads using this.
+struct ResourceProviderImpl::Data : public base::RefCounted<Data> {
+ public:
+  mojo::Array<uint8_t> data;
+
+ private:
+  friend class base::RefCounted<Data>;
+
+  ~Data() {}
+};
+
+ResourceProviderImpl::ResourceProviderImpl(
+    const base::FilePath& application_path,
+    base::SequencedWorkerPool* blocking_pool)
+    : application_path_(application_path),
+      blocking_pool_(blocking_pool),
+      weak_factory_(this) {
+  CHECK(!application_path_.empty());
+}
+
+ResourceProviderImpl::~ResourceProviderImpl() {
+}
+
+// static
+void ResourceProviderImpl::ReadFileOnWorkerThread(const base::FilePath& path,
+                                                  scoped_refptr<Data> data) {
+  int64 file_size = 0;
+  if (!base::GetFileSize(path, &file_size) || file_size < 0 ||
+      file_size > std::numeric_limits<int>::max())
+    return;
+
+  data->data.resize(file_size);
+  if (base::ReadFile(path, reinterpret_cast<char*>(&data->data.front()),
+                     file_size) != file_size) {
+    data->data.reset();
+  }
+}
+
+void ResourceProviderImpl::OnReadFile(scoped_refptr<Data> data,
+                                      const GetResourceCallback& callback) {
+  callback.Run(data->data.Pass());
+}
+
+void ResourceProviderImpl::GetResource(const mojo::String& path,
+                                       const GetResourceCallback& callback) {
+  const base::FilePath resource_path(
+      GetPathForResourceNamed(application_path_, path));
+  if (resource_path.empty()) {
+    callback.Run(mojo::Array<uint8_t>());
+    return;
+  }
+
+  scoped_refptr<Data> data(new Data);
+  scoped_refptr<base::SequencedTaskRunner> runner(
+      blocking_pool_->GetSequencedTaskRunnerWithShutdownBehavior(
+          blocking_pool_->GetSequenceToken(),
+          base::SequencedWorkerPool::SKIP_ON_SHUTDOWN));
+  runner->PostTaskAndReply(
+      FROM_HERE, base::Bind(&ResourceProviderImpl::ReadFileOnWorkerThread,
+                            resource_path, data),
+      base::Bind(&ResourceProviderImpl::OnReadFile, weak_factory_.GetWeakPtr(),
+                 data, callback));
+}
+
+}  // namespace resource_provider